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  1. This dataset consists of groundwater levels measured within wells distributed across Watershed 3 at Hubbard Brook Experimental Forest from 2007-2020. Water levels are expressed as a depth (cm) from the soil surface. This dataset is a part of a larger project aimed at explaining the spatial and temporal variation in stream water chemistry at the headwater catchment scale using a framework based on the combined study of hydrology and soil development – hydropedology. The project will demonstrate how hydrology strongly influences soil development and soil chemistry, and in turn, controls stream water quality in headwater catchments. Understanding the linkages between hydrology and soil development can provide valuable information for managing forests and stream water quality. Feedbacks between soils and hydrology that lead to predictable landscape patterns of soil chemistry have implications for understanding spatial gradients in site productivity and suitability for species with differing habitat requirements or chemical sensitivity. Tools are needed that identify and predict these gradients that can ultimately provide guidance for land management and silvicultural decision making. Better integration between soil science, hydrology, and biogeochemistry will provide the conceptual leap needed by the hydrologic community to be able to better predict and explain temporal and spatial variability of stream water quality and understand water sources contributing to streamflow. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  2. Mineral weathering is an important soil-forming process driven by the interplay of water, organisms, solution chemistry, and mineralogy. The influence of hillslope-scale patterns of water flux on mineral weathering in soils is still not well understood, particularly in humid postglacial soils, which commonly harbor abundant weath- erable primary minerals. Previous work in these settings showed the importance of lateral hydrologic patterns to hillslope-scale pedogenesis. In this study, we hypothesized that there is a corresponding relationship between hydrologically driven pedogenesis and chemical weathering in podzols in the White Mountains of New Hamp- shire, USA. We tested this hypothesis by quantifying the depletion of plagioclase in the fine fraction (≤2 mm) of closely spaced, similar-age podzols along a gradient in topography and depth to bedrock that controls lateral water flow. Along this gradient, laterally developed podzols formed through frequent, episodic flushing by up- slope groundwater, and vertically developed podzols formed through characteristic vertical infiltration. We estimated the depletion of plagioclase-bound elements within the upper mineral horizons of podzols using mass transfer coefficients (τ) and quantified plagioclase losses directly through electron microscopy and microprobe analysis. Elemental depletion was significantly more pronounced in the upslope lateral eluvial (E horizon- dominant) podzols relative to lateral illuvial (B horizon-dominant) and vertical (containing both E and B hori- zons) podzols downslope, with median Na losses of ~74 %, ~56 %, and ~40 %, respectively. When comparing genetic E horizons, Na and Al were significantly more depleted in laterally developed podzols relative to vertically developed podzols. Microprobe analysis revealed that ~74 % of the plagioclase was weathered from the mineral pool of lateral eluvial podzols, compared to ~39 % and ~23 % for lateral illuvial podzols and vertically developed podzols, respectively. Despite this intense weathering, plagioclase remains the second most abundant mineral in soil thin sections. These findings confirm that the concept of soil development as occurring vertically does not accurately characterize soils in topographically complex regions. Our work improves the current understanding of pedogenesis by identifying distinct, short-scale gradients in mineral weathering shaped by local patterns of hydrology and topography. 
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    Free, publicly-accessible full text available November 1, 2024
  3. Chemical analyses were performed on sieved and dried soil samples collected for the Lateral Weathering project within Watershed 3, Hubbard Brook Experimental Forest, Woodstock, NH, USA from 2018-2020. Chemical information corresponds to horizons described in dataset HBR361, which were collected from pits described in the same dataset. Analyses include pH, C, N, exchangeable ions, secondary metals from citrate dithionite and ammonium oxalate in the dark, and total elemental content. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  4. Hbr363: WS3 One year of resin-extracted solutes from variably saturated soils The Lateral Weathering Study looks at spatial patterns of mineral weathering processes at Hubbard Brook Experimental Forest. This project is characterizing mineral and elemental depletion/enrichment, soil morphology and chemistry, solute transport, and groundwater chemistry along hydropedological gradients. This dataset provides the total elemental mass of inorganic solutes (Ca, Na, Mg, Al, Fe, Mn, P, and S) as well as dissolved organic carbon (DOC) that were extracted off resins installed into shallow groundwater wells (~30-100cm) in Watershed 3. Resin packs were deployed for a total of one year (August 2019-2020) with four consecutive deployment periods, to avoid overloading resin ion capacity. Total mass for each solute was accounted for an entire resin pack, which was 5cm in height and 5cm in diameter, containing approximately 90 g of resin. Resin packs were installed in three different topographic positions along three transects (sites = 9), to characterize solute mass fluxes through different hydropedological units. 
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  5. This dataset consists of chemical analyses of subsurface water samples collected from Watershed 3, Hubbard Brook Experimental Forest, Woodstock, NH, USA from 2009-2020. Samples include groundwater samples pumped from monitoring wells, grab samples of natural groundwater seeps, and soil water samples pumped from Prenart lysimeters. For samples from wells where water table was monitored, depth to water table is given. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  6. Soil pits and horizons were described and sampled as part of the Lateral Weathering project within Watershed 3, Hubbard Brook Experimental Forest, Woodstock, NH, USA from 2018-2020. Soil pits were dug and described using NRCS methods. When possible, physical samples were archived in the Hubbard Brook Sample Archive. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  7. This data package contains a 1 m LiDAR-derived digital elevation model (DEM) and a 1 m hydro-enforced DEM across Hubbard Brook EF. The LiDAR was collected during leaf-off and snow-free conditions by Photo Science, Inc. in April 2012 for the White Mountain National Forest (WMNF). These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  8. This is a dataset of soil saturated hydraulic conductivity (Ksat) collected from augered boreholes or installed groundwater wells in Watershed 3 of the Hubbard Brook Experimental Forest. Hydraulic conductivity describes the ability of a porous medium such as soil to transmit fluid. It is dependent on both fluid (e.g., viscosity) and porous medium properties, and is a key property for estimating subsurface flow rates. Measurements were collected from near the soil surface (10-15 cm depth) to several meters below the surface. Locations are provided for sites where the confidence in coordinates established by GPS was high. Soil horizons without subordinate designators are approximate since the characterization skill of observers varied. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES) and several other NSF grants over the period from approximately 2007 to 2019. The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  9. This dataset consists of chemical analyses of subsurface water samples collected from Watershed 3, Hubbard Brook Experimental Forest, Woodstock, NH, USA from 2009-2015. Samples include groundwater samples pumped from monitoring wells, grab samples of natural groundwater seeps, and soil water samples pumped from Prenart lysimeters. For samples from wells where water table was monitored, depth to water table is given. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 
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  10. Abstract

    Groundwater flow direction within the critical zone of headwater catchments is often assumed to mimic land surface topographic gradients. However, groundwater hydraulic gradients are also influenced by subsurface permeability contrasts, which can result in variability in flow direction and magnitude. In this study, we investigated the relationship between shallow groundwater flow direction, surface topography, and the subsurface topography of low permeability units in a headwater catchment at the Hubbard Brook Experimental Forest (HBEF), NH. We continuously monitored shallow groundwater levels in the solum throughout several seasons in a well network (20 wells of 0.18–1.1 m depth) within the upper hillslopes of Watershed 3 of the HBEF. Water levels were also monitored in four deeper wells, screened from 2.4 to 6.9 m depth within glacial drift of the C horizon. We conducted slug tests across the well network to determine the saturated hydraulic conductivity (Ksat) of the materials surrounding each well. Results showed that under higher water table regimes, groundwater flow direction mimics surface topography, but under lower water table regimes, flow direction can deviate as much as 56 degrees from surface topography. Under these lower water table conditions, groundwater flow direction instead followed the topography of the top of the C horizon. The interquartile range ofKsatwithin the C horizon was two orders of magnitude lower than within the solum. Overall, our results suggest that the land surface topography and the top of the C horizon acted as end members defining the upper and lower bounds of flow direction variability. This suggests that temporal dynamics of groundwater flow direction should be considered when calculating hydrologic fluxes in critical zone and runoff generation studies of headwater catchments that are underlain by glacial drift.

     
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